Method for the separation of alpha-terpineol from pine oil



Patented Jan. 14, 1930 V UNITED STATES PATENT OFFICE LEE "I. SMITH, OIKENVI L, NEW JERSEY, ASSIGNOR TO HERCULES POWDER. COMPANY, OFWILMINGTON, DELAWARE, A CORPORATION.OF DELAWARE mnon FOR THE SEPARATIONOF ALPHA-TERPINEOL FROM PINE OIL I No Drawing.

My invention relates to a method for the separation of alpha-terpineolfrom pine oil.

It is known that among other constituents pine oil contains alha-terpineol, which has a 6 boiling point of a out 218 C.Alpha-terpineol has been separated from pine oil by fractionation.However, such method of separation is unsatisfactory and uneconomicalfrom a practical standpoint. According to 10 my invention, I provide amethod for the separation from pine oil of alpha-ter'pineol incrystalline form by the practice of which the alpha-terpineol may berecovered with economy, both from the standpoint of cost and yield. I

In accordance with the method embodying my invention, pine oil, such asis obtained, for example, from pine Wood by any well known process, isfractionated and a fraction boiling within the range from about 205 C.to about 220 C. separated. Preferably the fraction separated will have aboilin range from about 214 C. to about220 The fractionation of the pineoil may be carried out with or without steam and is preferably carriedout under reduced pressure, though it will be understood that thefractionation may be carried out at atmospheric pressure. Fractionationunder reduced pressure is preferable because of higher yield ofalpha-terpineol and since lower temperatures may be used with lessdecomposition and polymerization and the products recovered possess amore pleasant odor and probably greater purity.

After separating the fractionfrom the pine oil, the fraction, which isrich in alpha-terpineol, is refri erated to a temperature within therange a out 0 C. to about 3 (3.. preferablyto about -15 C. As a resultof refrigeration the alpha-terpineol will crystallize and may beseparated from the mother liquor in crystalline form, by filtration orby centrifuging. Instead of refrigerating the pine oil fraction toeffect *crystalization, it may be merely cooled and then seeded with acrystal, preferably of alp'ha-terpinecl,

; which will cause the alpha-terpineol present in thq cut to crystallizeand enable its separai tion by filtration or centrifuging. If desired,

invention may be readily practiced without Application filed August 11,1927. Serial 110.2123.

the pine oil out seeded with alpha-terpineol may also be refrigeratedwith the result that 'the time required for crystallization of thealpha-terpineol present in the cut will be re duced.

Instead of seeding the pine oil fraction with a crystal ofalpha-terpineol, the alphaterpineol in the cooled fraction may be causedto crystallize by mechanical means, as by adding to the fraction a smallpiece of broken glass, a grain of sand or a crystalline fragment ofsalt, etc. Thus, it will be understood that when in the claims appendedhereto reference is madeto seeding in order to induce crystallization,it is intended also to include any mechanical means for inducingcrystallization.

In accordance with the method embodying my invention, a yield ofalpha-terpineol amounting to twenty'to thirty per cent or more of theoriginal pine oil may be obtained and the alpha-terpineol will besubstantially pure.

Further, the method in accordance with my the use of any particular formof apparatus and at a minimum of expense.

Having now fully described my invention, what I claim and desire toprotect by Letters Patent is:

1. The method of separating alpha-terpineol from pine oil, whichincludes fractionating the pine oil to obtain a cut rich inalpha-terpineol and. which will boil at normal atmospheric pressurelargely within the range about 205 C.220 G. and effecting thecrystallization of alpha-terpineol present in the cut.

2. The method of separating alpha-tar pineol from pine oil, whichincludes frac- 90 tionating the pine oil to obtain a out, which willboil at normal atmospheric pressure largely within the range about 214C.220 (1, and effecting the crystallization of alphaterpineol present inthe out.

3. The method of separating alpha-'terpineol from 'pin'e oil, whichincludes fractionating the pine oil under reduced pressure to obtain acut rich in alpha-ter ineol andv which will boil at normal atmosp ericpressure largely within the range about 205 G.220 C. and effecting thecrystallization of alpha-terpineol present in the cut.

4. The method of separating alpha-terpineol from pine oil, whichincludes fractionating the pine oil to obtain a cut rich inalpha-terpineol and which will boil at normal atmospheric pressurelargel within the range about 205 C.220 C. an seeding the cut to inducethe crystallization ofalphaterpineol present in the cut.

5. The method of separating alpha-terpineol from pine oil, whichincludes fractionating the pine oil under reduced pressure to obtain acut rich in alpha-terpineol and which will boil at normal atmosphericressure largely within the range a out 205 C.220 C. refrigerating, thecut and intionati I to ducing crystallization of alpha-terpineol presentin the cut.

6. The method of separating alpha-terpineol from pine oil, whichincludes fracthe pine oil to obtain a cut, boiling within t e range fromabout 214 C to about 220 (3., refrigerating the cut and mechanicaL' lyinducing crystallization of alpha-terpineol present in the cut.

7 The method of separating alpha-terpineol from pine oil, which includesfractionatin the pine oil to obtain a cut, boiling within t e range fromabout 214 C. to about 220 C. seeding the cut with a crystal ofalpha-terpineol and'refrigerating to efi'ect crystallization ofalpha-terpineol present in the cut.

8. The method of separating alpha-ter-

